The present invention relates to a picture recording apparatus for producing photographic hard copies from television image signals of a still picture reproduced on a screen of a television monitor. More particularly, the present invention relates to a picture recording apparatus capable of magnifying a part of the reproduced picture in order to make analysis of reproduced picture or picture quality adjustment thereof easy.
In an X-ray diagnosis, ultrasonic diagnosis, computer tomography and radioisotope diagnosis, in general, there has generally been a trend toward obtaining recorded pictures by projecting images reproduced on a display screen of a television monitor onto a recording medium for example, a photographic film. One shortcoming with this approach is that the raster of such a monitor typically has scanning lines of 525 line/frame such that raster lines are remarkably visible on the recorded picture, resulting in a difficulty in observing the recorded picture. The conventional picture recording apparatus, therefore, typically employs means for reproducing images in such a fashion that raster lines of the reproduced image displayed on the screen are not remarkably visible, for example, by using pseudo interlacing or raster erasing.
In one example shown in Japanese Patent Application Publication No. 57025/83, there was proposed a raster erasing method in which image signals of a plurality of same rasters are reproduced on a screen of a display tube in the vertical scanning direction and so as to adjoin rasters of a respective frame. This raster shifting and multiplication is; equivalent to the case of increasing the number of lines of the reproduced image. Another raster erasing method, in which intervals between rasters adjacent to the picture of the same frame are made invisible, by making the scanning beam width of the display tube wide or by adding wobbling. The picture recording apparatus using one of the above described raster erasing methods is effective in making the presence of raster line invisible on the recorded picture obtained as a hard copy. One shortcoming, resulting from the raster approaches, is that it is impossible to observe the raster reproduced on the display tube of the television monitor with the naked eye. As such it is difficult to observe whether the raster lines are inserted with equal interval, resulting in a problem of being incapable of observing whether images reproduced on the display tube are adjusted with high precision.
The above conventional picture recording apparatus is not easy to handle. First, no provision is made for supplying means for adjusting respective portions of the image reproducing system in the picture recording apparatus with precision. More particularly, no provision is made for supplying observing means for analyzing a part of the reproduced image by magnifying the part thereof in any direction, while viewing images reproduced on the display tube of the television monitor.